Giáo trình Java cơ bản 01

Welcome to Object-Oriented Programming Using Java... 1/4 Subject aims  To understand how computers work  To develop techniques for solving problems using a computer  To develop skil

Welcome to Object-Oriented Programming

Using Java

► Subject Information

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Subject aims

 To understand how computers work

 To develop techniques for solving problems using a computer

 To develop skills in algorithm development

and object-oriented programming using the

Java language

 To gain experience in engineering reliable

programs

… in particular

 OOJ/OJA and IPJ/IJA have been designed

to form the core of Java programming

 They provide a solid foundation for Java

application development

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Teaching philosophy

 Learning is an active process

 The role of the teaching staff is to assist

students to learn

 Students must be driven and

self-managed

 Learning in groups is a positive experience

 Problem solving and programming are best

learnt by practice

References

 Textbook

– Walter Savitch, Java: An Introduction to Computer

Science & Programming (Third Edition), Pearson, 2004

– Harley Hahn, Student Guide to Unix, McGraw-Hill, 1996

– Steve Oualline, Vi IMproved – Vim, New Riders, 2001

( http://www.newriders.com/books/opl/ebooks/0735710015.html )

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What is expected from you?

 An interest in the material

 Participation in labs and lectures

 Be aware of the learning environment you

share with other students

– No disruptive behaviour

Overview of OOJ/OJA

 Introduction to Computer Systems,

– Unix Environment and Java Programming

 Primitive Data Types

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►Computer Systems and

Structure

What is a computer?

 A computer is a device for storing and

processing information

 When connected to networks, a computer

becomes a versatile communication tool

 When connected to other devices, a

computer can act as a sophisticated

device-controller

 Java provides facilities to write programs to

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Hardware and software

 A computer consists of hardware and

software

 Hardware consists of the physical

components that make up the computer

 Software consists of programs that control

the hardware to do useful work

 Programming (or coding) is the process of

writing software

Examples of hardware

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Typical components in a PC

CD-ROM drive

Disk drives

Main hardware components

 CPU - Central Processing Unit

– Executes program instructions

 RAM - Internal memory

– Stores programs that are currently being run and data

associated with those programs

– Volatile

 I/O (Input/Output) devices

– Allow information to be input to the computer (e.g

keyboard, mouse, scanner)

– Allow information to be output by the computer (e.g

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Main hardware components

 Secondary storage (or external memory)

– Disk, tape, CD-ROM

– Larger, slower, cheaper than internal memory

– For storage of programs and data not currently

in use

 Bus

– Transmits data and instructions between the

CPU and memory

– n address bits means we can address 2 n memory

locations labelled 0 to 2n - 1

Terminology and functionality

 Files and directories

– Ways of storing and organising data and

programs on secondary storage

– Covered in detail in laboratory classes

 Peripheral devices

– Collective name for secondary storage and I/O

devices

Binary representation

 Inside the computer, data and instructions

are represented as bit patterns

byte 8

3 byte location with address 1

2 byte location with address 4

1 byte location with address 6

3 byte location with address 7

– High-level languages (such as Fortran, Cobol,

Pascal, C, C++, Java, etc.)

 Each programming language has a defined

set of rules that govern the structure of its

program

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 A group of bytes (i.e a sequence of bits) can

represent many different things: a number *,

a character, a string, a picture, a sound track,

a video, or a program instruction

* a real number (one with a fractional part) is represented

by two sequences of bits, one for the mantissa and one for the exponent

 e.g the bit sequence 01000001can be

Algorithms

 Consider the algorithm (an unambiguous

sequence of instructions to perform some

task)

Pseudocode

IF X equals Y THEN

Assign zero to Z ELSE

Assign Y / (X - Y) to Z ENDIF

{next statement}

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System software

 Supports basic operations of the computer

such as managing resources, allowing

transfer of information to and from the

computer

 Examples

– Operating systems (e.g Unix, Windows)

– Communication software (to connect to other

computers and the Internet)

– Compilers (translate high-level programs into

executable code)

– Other programs, for example programs to

support operations of organisations

Next lecture

 Operating systems

 The Unix operating system

 Compiling and running Java programs